PyQt5 QML 树视图示例

Question

我尝试使用PyQt5.6（Python 3.4）和QML设置一个简单的树视图示例。我只是找到了几个C++的例子，但没有一个与 PyQt 相关。我拿起了 PyQt 源代码附带的简单树模型示例并对其进行了修改（https://github.com/baoboa/pyqt5/tree/master/examples/itemviews/simpletreemodel）。

模型很可能有问题。我收到两条错误消息：

simpletreemodel.qml:13:5: QML TreeView: Binding loop detected for property "model"

...qt/5.6/gcc_64/qml/QtQuick/Controls/TreeView.qml:94:16: Unable to assign [undefined] to QAbstractItemModel*

知道发生了什么和/或错误吗？qml 树视图刚刚在 Qt 5.5 中引入，也许它在 PyQt 中没有完全工作？！没有找到任何相关信息。

这是我的代码：

simpletreemodel.qml

import QtQuick 2.5
import QtQuick.Controls 1.4
import QtQml.Models 2.2
Rectangle {
    width: 480
    height: 640
    TreeView {
        id: treeView
        anchors.fill: parent
        anchors.margins: 6
        anchors.top: parent.top
        anchors.horizontalCenter: parent.horizontalCenter
        model: model
        TableViewColumn {
            title: "Title"
            role: "TitleRole"
            resizable: true
        }
        TableViewColumn {
            title: "Summary"
            role: "SummaryRole"
            resizable: true
        }
    }
}

simpletreemodel.py

#!/usr/bin/env python
from PyQt5.QtCore import (
    QAbstractItemModel, QFile,
    QIODevice, QModelIndex, Qt,
    QUrl
)
from PyQt5.QtGui import QGuiApplication
from PyQt5.QtQuick import QQuickView
import simpletreemodel_rc
class TreeItem(object):
    def __init__(self, data, parent=None):
        self.parentItem = parent
        self.itemData = data
        self.childItems = []
    def appendChild(self, item):
        self.childItems.append(item)
    def child(self, row):
        return self.childItems[row]
    def childCount(self):
        return len(self.childItems)
    def columnCount(self):
        return len(self.itemData)
    def data(self, column):
        try:
            return self.itemData[column]
        except IndexError:
            return None
    def parent(self):
        return self.parentItem
    def row(self):
        if self.parentItem:
            return self.parentItem.childItems.index(self)
        return 0

class TreeModel(QAbstractItemModel):
    def __init__(self, data, parent=None):
        super(TreeModel, self).__init__(parent)
        self.rootItem = TreeItem(("Title", "Summary"))
        self.setupModelData(data.split('n'), self.rootItem)
    def roleNames(self):
        roles = {
            Qt.UserRole + 1: b"TitleRole",
            Qt.UserRole + 2: b"SummaryRole"
        }
        return roles
    def columnCount(self, parent):
        if parent.isValid():
            return parent.internalPointer().columnCount()
        else:
            return self.rootItem.columnCount()
    def data(self, index, role):
        if not index.isValid():
            return None
        if role != Qt.DisplayRole:
            return None
        item = index.internalPointer()
        return item.data(index.column())
    def flags(self, index):
        if not index.isValid():
            return Qt.NoItemFlags
        return Qt.ItemIsEnabled | Qt.ItemIsSelectable
    def headerData(self, section, orientation, role):
        if orientation == Qt.Horizontal and role == Qt.DisplayRole:
            return self.rootItem.data(section)
        return None
    def index(self, row, column, parent):
        if not self.hasIndex(row, column, parent):
            return QModelIndex()
        if not parent.isValid():
            parentItem = self.rootItem
        else:
            parentItem = parent.internalPointer()
        childItem = parentItem.child(row)
        if childItem:
            return self.createIndex(row, column, childItem)
        else:
            return QModelIndex()
    def parent(self, index):
        if not index.isValid():
            return QModelIndex()
        childItem = index.internalPointer()
        parentItem = childItem.parent()
        if parentItem == self.rootItem:
            return QModelIndex()
        return self.createIndex(parentItem.row(), 0, parentItem)
    def rowCount(self, parent):
        if parent.column() > 0:
            return 0
        if not parent.isValid():
            parentItem = self.rootItem
        else:
            parentItem = parent.internalPointer()
        return parentItem.childCount()
    def setupModelData(self, lines, parent):
        parents = [parent]
        indentations = [0]
        number = 0
        while number < len(lines):
            position = 0
            while position < len(lines[number]):
                if lines[number][position] != ' ':
                    break
                position += 1
            lineData = lines[number][position:].trimmed()
            if lineData:
                # Read the column data from the rest of the line.
                columnData = [s for s in lineData.split('t') if s]
                if position > indentations[-1]:
                    # The last child of the current parent is now the new
                    # parent unless the current parent has no children.
                    if parents[-1].childCount() > 0:
                        parents.append(parents[-1].child(parents[-1].childCount() - 1))
                        indentations.append(position)
                else:
                    while position < indentations[-1] and len(parents) > 0:
                        parents.pop()
                        indentations.pop()
                # Append a new item to the current parent's list of children.
                parents[-1].appendChild(TreeItem(columnData, parents[-1]))
            number += 1

if __name__ == '__main__':
    import sys
    app = QGuiApplication(sys.argv)
    view = QQuickView() 
    f = QFile(':/default.txt')
    f.open(QIODevice.ReadOnly)
    model = TreeModel(f.readAll())
    f.close()
    root_context = view.rootContext().setContextProperty('model', model)
    view.setSource(QUrl.fromLocalFile('simpletreemodel.qml'))
    view.show()
    sys.exit(app.exec_())

Answer 1

root_context = view.rootContext().setContextProperty('model', model)

不要使用模型作为模型的名称。